For several months now, I have not gotten audible alerts for e-mail or Ring Doorbell or any other application. The only audible alert I get is that my phone rings when I get a call but it also does not give an audible alert when a call is missed.

I get only vibrations.

I'm sure I have turned off this somehow and don't know how or when. I've been through the settings as best I can with no luck.

EDIT: I just now noticed that when I am selecting my default notification sound in settings, it does not play the sounds as I select them. None of them play. They are totally silent.

When I select the phone ring tone in settings it does play.

 

I found the problem and fixed it easily.

I discovered quite by accident that the volume for notifications was turned all the way down and had been that way for months.

I have no idea how that happened and didn't know that volume for notifications was a separate volume control.